The death toll in a huge explosion that rocked Kabul’s diplomatic quarter has risen to 90 with another 400 people injured, Afghanistan’s Public Heath Ministry has said, in what is believed to be one of the worst terror incidents to ever hit the Afghan capital.

The massive blast near the German embassy in Zanbaq Square sent thick plumes of smoke into the sky and managed to shatter windows and blow doors off their hinges one kilometre (half a mile) away. Makeshift ambulances struggled to deal with the number of casualties as the vast scale of the damage became clear.

Video from the scene showed a number of dazed, bloodsoaked people stumbling around and bodies still lying on the ground or in burning cars. The majority of the dead are thought to be civilians. Women and children were among those killed, Ismail Kawasi of the Public Health Ministry said.

At least one journalist working for local Tolo news agency was confirmed to have died. German security sources said that an Afghan security guard at the embassy had been killed and several German staff hurt.

“The attack took place very close to the German embassy. It hit civilians and those who are in Afghanistan to work for a better future for the country with the people there. It’s especially contemptible that these people were the target,” German Foreign Minister Sigmar Gabriel said on Twitter.

Germany’s Interior Ministry said deportations of Afghans whose asylum requests have been rejected have been temporarily suspended in the wake of the attack.

The Japanese embassy confirmed two nationals had been wounded, as was one Pakistani embassy employee, and heavy damage was sustained by the nearby British, Turkish and Chinese embassies as well as the AFP news agency’s offices.

It is understood that Turkey plans to evacuate some of its staff from the city following the incident.

The death toll is expected to rise, the Interior Ministry said, putting out an urgent appeal for blood donors.

There has been no immediate claim of responsibility for the attack – although the Taliban has denied involvement, making it more likely Isis is to blame.

Spokesperson Zabihullah Mujahid said that Wednesday’s explosion had “nothing to do with the Mujahedeen of Islamic Emirate,” as the Taliban calls itself. While the militant group claims only to wage war on the US-backed government and occupying foreign forces, civilians usually bear the brunt of the carnage, and the attack bore resemblances to other recent Taliban violence.

It is not uncommon for Isis to wait a day or two before claiming responsibility for attacks.

The latest terror incident is thought to be one of the deadliest to ever hit Kabul. Prior to the attack, a total of 220 people had died in extremist violence in the capital since April 2015. Last July two Isis suicide bombers blew themselves up during a Shia protest march, killing 80 people and wounding a further 230.

It is not clear what the attacker’s intended target was. Recent incidents targeting foreigners inside the heavily fortified diplomatic district – supposedly the capital’s safest area – have been claimed by both groups.

The latest explosion is sure to raise questions about existing security procedures.

On Wednesday afternoon the interior ministry confirmed local media reports that a sewage tanker was packed with explosives then detonated at a busy intersection, leaving a crater five metres (16ft) deep.

In a statement the Afghan government condemned the attack, saying: “Today the enemies of Afghanistan once again showed their brutality by killing and wounding civilians. The enemy has no mercy on civilians.”

Afghanistan as a whole has seen of a wave increasing violence in the past 12 months as both Taliban and Isis militants struggle to overthrow the government and impose Islamic law.

In recent years jihadi groups have increasingly called for attacks on civilians during the holy month of Ramadan, which began on Saturday. A suicide bomber killed 26 people breaking their fast and enjoying ice cream at a shop in the Iraqi capital of Baghdad on Tuesday.

“The terrorists, even in the holy month of Ramadan, the month of goodness, blessing and prayer, are not stopping the killing of our innocent people,” President Ashraf Ghani said.

Although the Taliban lost control of Afghanistan following the US invasion of 2001, it has steadily regained ground since most international troops withdrew in 2014 and other extremists such as Isis have also flourished. Islamists are currently in control of around 40 per cent of Afghanistan, although they hold no major cities.

Last month the group announced a spring offensive which would target foreign forces in the country.

There are currently around 13,000 US and Nato ally troops deployed to Afghanistan, although the Pentagon has urged US President Donald Trump to send more soldiers to combat the deteriorating security situation.